It is known, especially in the case of parts which are screwed together, such as valves, fittings, pipe sections and the like, to apply a liquid sealant to the appropriate threaded sections before screwing them together, and then screwing the parts together. The result is a chemical binding of the sealant, e.g. in the presence of iron or copper or exclusion of O.sub.2 (e.g., Loctite). In this method of producing tight connections, however, the plumber is advised to apply the sealant on the job (for example, in liquid form) to the corresponding parts; this is time-consuming, and expensive and unacceptable as far as tightness is concerned. Sealing on the job by means of hemp, PTFE tape and the like can also be mentioned as known.